Polar lipids of non-alkaliphilic Halococci

Abstract

Until recently, only one species of Halococcus has been recognized, namely, H. morrhuae, but a large number of extremely halophilic non-alkaliphilic cocci have now been isolated from hypersaline habitats in Spain and classified into four phenons (A-D); one of the phenon D strains has been classified as a new species, Halococcus saccharolyticus. Examination of the lipids of H. saccharolyticus and four strains of phenons A-C showed the presence in all of them of C20-C20 and C20-C25 diether molecular species of phosphatidylglycerophosphate (PGP), phosphatidylglycerol (PG) and phosphatidic acid (PA); a monounsaturated isoprenoid C20-C20 (phytanyl-phytenyl) species of PGP; a sulfated diglycosyl diphytanylglycerol (S-DGD) with structure 2,3-diphytanyl-1-(6-HSO3-mannosyl-1-2-glucosyl)-glycerol, which is identical to the S-DGD-1 in Haloferax mediterranei; a phosphoglycolipid (P-TGD) tentatively identified as a phytanyl-phytenyl-(H2PO3-galactosyl-mannosyl-glycosyl)-glyce rol, and two unidentified glycolipids present only in traces. No phosphatidylglycerosulfate (PGS) was detected in any of the strains examined. This pattern of lipids appears to be characteristic of the strains of Halococcus from salterns in Spain, but studies of a larger number and variety of Haloccus are necessary to establish this conclusion with certainty.